Phosphate in food is ‘health risk’ that should be labelled, claim researchers

Food products with high phosphate contents are damaging to the health of the general public, and as such should be labelled, say researchers behind a new study.

The report – published in Deutsches Ärzteblatt International ​– selectively reviewed research documenting the links between excessive phosphate and elevated risks of ill health and mortality – calling for a ‘traffic-light’ labelling system to be introduced for foods containing phosphate additives.

The researchers, led by Professor Eberhard Ritz of Nierenzentrum Heidelberg, Germany, reported that elevated serum phosphate concentrations have been found to be correlated with mortality in people with chronic renal failure, while high levels of phosphates in healthy people have been correlated with cardiovascular disease.

Ritz and his colleagues said they believe that “the ​public should be informed that added phosphate is damaging to health.” ​​“Furthermore, calls for labelling the content of added phosphate in food are appropriate,”​ they added.

Phosphates​

Natural (organic) phosphate esters are found mainly in protein-rich foods, including dairy products, fish, meat, sausages, and eggs. Ritz and his team explained that these compounds are slowly broken down in the gastrointestinal tract and then slowly resorbed from the intestine.

“About 40% to 60% of the organic phosphate esters consumed in the diet are resorbed,”​ they said.

However, they noted that the phosphate content of industrially processed food is much higher than that of natural food, because polyphosphates are commonly used as an additive in industrial food production. Such ingredients can legally be added to food as preservatives, acidifying agents, acidity buffers, and emulsifying agents, whilst phosphate salts are also used in foods to intensify flavours, they said.

Phosphate additives also play an especially important role in the meat industry, where they are used as preservatives. They are also used as a component of melting salts in the production of soft cheeses and are found in flavoured soft drinks and powdered products.

“Because of the increased use of food additives, the estimated daily intake of phosphate-containing food additives has more than doubled since the 1990s, from just under 500 mg/day to 1000 mg/day,”​ said Ritz and colleagues.

They noted that over 300 food additives have been approved for use in the European Union, with each given a “uniform designation”​ E number which must be marked on food packaging.

“The labelling requirement is, unfortunately, only qualitative, and not quantitative,”​ said the researchers. “The consumer ... cannot determine how much phosphate is actually present in each item, as neither the overall phosphate content nor the quantity of added phosphate is indicated.”​

‘Need for action’​

“In view of the known connection between dietary phosphate and organ calcification in patients with renal failure, as well as the growing realization that phosphate can damage health even in persons with normal kidneys, one may ask whether concrete interventions in health policy ought to be taken now, even though such steps cannot yet be supported by any findings from prospective interventional trials,”​ said Ritz.

The authors said one important step would be to inform physicians and the public thoroughly about the potential risks to cardiovascular and renal function arising from dietary phosphate consumption. However they added that “comprehensive labelling of phosphate additives in food – ideally, with a “traffic-light” scheme – would also be desirable.”​

“The amount of added phosphate, whether low, medium, or high, should be indicated with a green, yellow, or red sign on the package,”​ they said noting that Finland and the United Kingdom already use similar systems to indicate salt content.

“In order for such measures to be implemented, support should be sought from the food industry, consumer protection organizations, medical societies, and governmental and quasi-governmental entities,”​ said Ritz and his team.